This invention relates broadly to the art of bucket conveyors, and more particularly to continuous loading systems for bucket conveyors.
It is generally recognized that bucket conveyors are more difficult to load than many other types of endless conveyors in that bucket conveyors normally have spaces between the buckets through which material falls if an attempt is made to continuously load the buckets. Notwithstanding this disadvantage, bucket conveyors are often used where granular, and/or fluid, material must be conveyed upwardly. Although it is possible to stop each bucket at a loading station, such a loading procedure slows the conveyor an unacceptable amount for many applications.
Attempts have been made to continuously load bucket conveyors by putting the buckets extremely close to each other and allowing lips of the buckets to overlap when the buckets are traveling in a horizontal manner, such as is disclosed in U.S. Pat. No. 3,795,305 to Sandvik. This system has been relatively successful, however, it has the disadvantage that the buckets thereof cannot rotate 360.degree. without contacting adjacent buckets and rotation of the buckets must, therefore, be strictly controlled. Such bucket-attitude-control equipment, including special cammed buckets, is unduly expensive and, therefore, drives up costs. Further, the buckets in such a bucket conveyor sometimes rotate in improper manners due to malfunctions and cause adjacent buckets to become "jammed" together. Malfunctions such as these can "pop" the buckets from conveying chains and these loose buckets can further "jam up" other buckets, popping them from the chains. If appropriate action is not taken, all the buckets can be "stripped" from the chains. It is, therefore, an object of this invention to provide a bucket conveyor in which the buckets and bucket-attitude-control equipment is relatively inexpensive and uncomplicated. It is a further object of this invention to provide a bucket conveyor whose buckets cannot come into contact with adjacent buckets when they rotate through 360.degree..
It has been suggested that buckets of a bucket conveyor can be continuously loaded by employing an additional endless conveyor having covers attached thereto for covering spaces between buckets at loading zones. In this regard, the cover endless conveyors are mounted above a horizontal portion of a bucket endless conveyor so that covers of a bottom flight of the cover endless conveyor correspond with spaces between buckets of a top flight of the bucket endless conveyor. Such systems are disclosed in U.S. Pat. No. 4,221,764 to Saxon, U.S. Pat. No. 658,657 to LeGrand, and U.S. Pat. No. 618,343 to Haiss. U.S. Pat. No. 2,476,039 to Hapman discloses a similar system although in this patent the cover is not attached to an endless conveyor but rather to a reciprocating member which is reciprocated over a bucket space at a loading zone. A difficulty with such prior-art systems is that they have tended to take up too much room by having a cover endless assembly above a bucket endless assembly. In addition, they have tended to be too complicated by requiring unusual structures for feeding material between top and bottom flights of cover conveyors to be loaded into the buckets. Concerning complexity of feeding mechanisms, the Saxon patent calls for either feeding through both upper and lower flights of a cover endless conveyor (Saxon FIG. 1) or utilizing a screw conveyor (Saxon FIG. 7) to convey material between conveyor flights. The LeGrand and Hapman patents require hoppers to be positioned between conveyor flights, immediately above buckets to be loaded, which may be inconvenient or impossible in many situations because of space requirements. The Haiss patent appears to call for a mechanism for "throwing" material into a drum (see page 2, lines 97-104 of Haiss). It is, therefore, an object of this invention to provide a continuous-feed assembly for a bucket endless conveyor which does not take up an unduly large amount of space and is not unduly complex.
In addition, it is an object of this invention to provide such a bucket endless conveyor feed mechanism which is effective in operation, spilling virtually none of the fed material onto a floor.
It is a further object of this invention to provide such a continuous-feed bucket conveyor which is relatively uncomplicated and economical to manufacture.